Drier heating system



Patented Sept. 7, 1948 UNITED Stmas PATENT ferries 2,448,170 DRER HEATING SYSTEM Richard D. Cheesman,

the character used in the manufacture of cement, especially those `with high Water content, are difficult to calcine because their physical characteristics changeas the moisture is extracted. extremelytacky and adhere to the interior sur# face of the kiln forming what is known to the trade as slurry or mud rings. On this account it has been found desirable to pre-dry the slurry to a moisture content at which this tackiness is avoided in the calcining operation. A satisfac tory form of drier for this purpose is disclosed in Patent No. 1,992,520, granted February Y26, 1935, to Colton and Lang. The drier of the vsaid patent is adapted to be arranged in receiving relation to the hot waste gases `flow-ing from the kiln so that these gases are used as the sole heating means for the drier.

In such an arrangement in that the temperature and heat content of the waste .kiln -gases vary'on accoun-trof several fac-f 19,0115, for.examplatheradiatlon losses Viromvthe kiln shell, the chemical composition and reaction of .the material being calened or sintered, the variation of the moisture content of the slurry, and the neness of the material. All of these factors influence the regulation of the kiln burner` and thus cause variations in theheat content and temperature of waste or rflue gases from the kiln.

In theaboveementioned patent, control is attempted to be maintained by means of (lampe-rs disposed in the conduit leading from the kiln to the drier and in a by-pass conduit. However, these provisions are inadequate to aiord th ref quired pre-drying temperature when the total heat eiect of the waste kiln gases is inadequate, and it is the object of the present invention to provide means whereby requisite drying heat is assured. To this .endl provide means for supplying supplemental heat tothe drier, the supplementalsupply being preferably automatically regulated and inversely in dependence upon the temperature of the waste gases flowing from the Certain slurries of a complication arises kiln, and at least being controlled by. reference to the temperature of these gases. I `also provide dampers in the supply and lay-pass conduits and these may be automatically adjustable interdependently with the auxiliaryheat supply. The improvements are Shown in illustrative embodi- Some of them become t Allcntown,' Pa., assigner to Traylor Engineering Pa., a corporation of Delaware ment in the accompanying drawings J9o which reference will now be made. In these drawings,

Figure l'is an elevation, partly in section, of an installation in accordance with the inven. tion;

Figure 2 is a Section substantially on line 2-.2 0f Figure l: l

Figure 3 is an axial section of a drier which appears inFsure ,1, and

Figure 4 is anend elevation* of the drier of Figure 3 as seen from the left of that figure.

Referring to the drawings, reference numeral Il designates a conve tional rotary kiln, and IZ a regulable burner. The latter may be of any suitable design and. for example, may be like that shown in my prior `Patents No. 1,949,560 or Nof 1,989,665, The feed end-0f kiln is disposed in a. side opening of a chamber I3 provided fwith an opposite openingin which is set an elbow I4 iormingpart of a waste iiue which includes an upright ley-pass conduit section I5. Above chamber rI3 is a drier generally designated by reference numeral lli.

The drier I6 comprisesarotary drum I1 having at itsends tires it and Iiisupported on rollers 20 and "2l, the drum being driven from a motor 22 and gearing terminating at a ring gear 23 secured to the drum. The drum is surrounded by a housing 24 comprising a peripheral shell 25 land annular Vend Walls 26 and 21 provided with channeled inner edges in which are engaged annular flanges 28 and 29 on the drum, this interleaving arrangement providing relatively gas tight joints. inwardly of the flanges 28 and 23 the drum is provided with circumferential series ofopenings 30 and 3l and, just inwardly of these latter, with inwardly projecting annular flanges 32Vv and 33, Just-outwardly of the openingsV 39 and 3i the druml is `provided with inwardly projecting yannular iianges 34` and 35 which form a relatively vgas-.tight joint with circular end walls or plates 36 and 31 iixedly supported on brackets 38 and 39.

A shaft 4l) jcurnaled in bearings 4| and 142 extends throughopenings in walls 36 and 31 and the bottom o'f the drum, and is adapted to be rilrivenffrom` a motor 43. Shaft `lll is parallel to the drinn axis and beneath the latter. Within vflanges 32 and 33 shaft 4D carries two series of paddles or arms 44 and 4'5. Aieed spout 4t extends through an opening in wall l31 'and is downwardly and inwardly inclined with its delivery end adjacent the top of the paddles 45 on the down-traveling side of the latter. Material delivered through the drum is agitated by the paddles 44 and I45 and is moved by the paddles, which are suitably formed for the purpose, over the bottom of the drum in opposite directions to discharge over the bottom portions of rings 32 and 33 to drop through openings 30 and 3| and through openings 41 and 48 of the housing `shell 25 to drag conveyors 49 and 50 which deliver to a screw conveyor 5.1, Figure 1. The latter delivers to a spout 52 which is passed through the top of chamber I3 and into the feed end of the kiln.

Leading upwardly from elbow I4 to an opening 54 in the bottom of the housing shell 25, is a conduit 53 having a ared upper portion 53. Fixed to the interior o'f the housing between opening 54 and the openings 30 of the drum is an annular radially arranged stantially closes the space and the drum. Hot gases supplied through conduit 53 will thus owcompletely around the drum periphery Aso that the latter will 'be' heated throughout. Restrained by baille 55 against "escape through drum openings 30, thezgases will then ilow to the drum interiorthrough openings` 3|, escaping through openings 3i! to an exhaust' opening 56 in the top of shel1'25 Vbetween wall 26 and baille 55 whence the gases pass throughl an elbow 51, Figure 1, to a conduit or ilue 58 into which the by-pass conduit I is connected. Radial wings I1 and I1 on the drum keep the conduits through which the gases-passend the material is discharged clearat the ends, preventing the spray from buildingup and lling thelower parts.

Reference numeral 51", Figure 1, designates a Y dust conveyor in receiving relation to chamber I 3 and elbow I4 through conduits 58 and 59, which may be dampered. i

Portion 53 of conduit y53A against the outer margins of which is set the open end of the combustion chamber 6I of a burner or booster furnace 62. A fuel nozzle 63 for gas or oil, for example, is disposed at the other end of chamber 6I and is equipped with a control valve SII-including a rotary spindle B5 by rotation of which the fuel supply may be regulatedl progressively between zero and maximum. A valved line 66 isconnected into the valve '64 from the fuel supply; H

Located in conduitportion 53 61 projecting into the conduit to one side of the stream of hot gases. The reactions'of the thermostat are communicated vto a controller" 68 through a line 69, the controller having a rock shaft actuated in Shaft 10 `is parallel to a two-armed lever of` nectedby a link spindle.

the spindle 65 and' carries which one arm 1I isV con- 12 with an arm 13 xed on the In the relation of the'pa'rts shown in Figure l the controller is assumed to'have been operated to maximum', shaft 10 turning clockwise, so that the fuel supply to the burner 62 is at maximum.

Arm 'II is alsoconnected through a link 13 with an arm 14 onthe shaft of a damper 15in bypassconduit I5, and with valve'64 fully open,'the damper is in the fully closed position shown.

The other arm 16 of the controller lever is connected by a link '11 with an armj18 on the shaft of a damper 19 in conduit 53; the damper being the spout to the interior of is a thermostat response tov the thermostat. `60

baille 55 which subbetween the housing has an opening 5B wide open in conformity with the wide open position of the valve @4 and the closed position of damper 15.

Should the temperature of the flue gases rise, controller shaft 10, as affected by the reaction of the thermostat, will turn in a counter-clockwise direction so that valve 64 and damper 1S will be accordingly moved toward closed position whereas damper 15 will be accordingly moved in the opening sense. Thus, with the hookup as illustrated, the auxiliary fuel supply valve and the two dampers are interdependently and automatically operated to control the heat supply to the drier inversely in dependence upon the temperature of the ue gases. Links 13 and 11 can be removed so that the dampers can be independently manually operated, or automatic operation can be applied to only one of the dampers by removing the operating link for the other. If it should be desired to operate valve 64 manually, for example, upon failure of the thermostat, the link 12 is removed and valve 64 is then manually adjusted by reference to a thermometer set in conduit portion 53' adjacent the thermostat.

By reason of the regulable auxiliary heat supply, uniform drying conditions are main-- tained at the drier and the resulting slurry fed to the kiln is of uniform temperature and moisture content, insuring the calcining operation in the kiln under the most favorable conditions. The usual rings of accretions at the feed end of the kiln are entirely eliminated.

While I have disclosed the invention in preferred embodiment it will be understood that it is not necessarily limited to the described form and relation vof the parts and that variations are possible and are contemplated under the claims which follow.

I claim: y

1.In combination, a kiln, means for supplying heat to the kiln, a drier for slurry to be fed' to the kiln, a conduit for leading Athe hot gases from the kiln to the drier, a by-pass conduit, dampers in said conduits respectively, an auxiliary heater with variable output arranged to deliver to said first mentioned conduit, whereby to supplement the heat of said gases, `and means for interdependently controlling said heater and dampers.

2.A In combination a kiln, means for supplying heat to the kiln, a drier for slurry to be fed to the kiln, a conduit for leading the hot gases from the kiln to the drier, a by-pass conduit, dampers in said conduits respectively, an auxiliary heater with variable output arranged to deliver to'said rst mentioned conduit, whereby'to supplement the heat of said gases, and means responsive to the temperature of said'gases for interdependently controlling said heater and dampers in a mannerv to augment the heat supply to the drier when said temperature falls.

In combination, a kiln, means for supplying heat ing heat to the kiln,

in said conduits respectively, an auxiliary burner arranged to deliver to said rst mentioned conduit, whereby to supplement the heat of said gases, va fuel supply valve for said burner, a controller operated in response to the temperature in the first-named conduit, and operating connections from said controller to said valve and dampers.

RICHARD D. CHEESMAN.

REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS Name Date Uhle Apr. 21, 1931 De Baufre Dec. 15, 1931 Arnold Jan. 22, 1935 Lee Feb. 18, 1936 Smith Jan. 19, 1937 Ahlmann Aug. 2, 1938 Bussmeyer May 9, 1939 Pike Sept. 10, 1940 Treshow Oct, 14, 1941 

